I don't like that one since "x and g" are just as arbitrary as the original and thus not mnemonic.

Here's an idea: base it on a sequence of events, that would occur in a natural order based on a scenario.

Here's an incomplete start: "I was listening to the radio one night, and an add for <whatever silly thing> made me hungry! So I went to the kitchen and popped some frozen <whatever> into the Microwave to make a snack. Then the snack became hot (think IR == heat) and burned my hand. I was already sore from sunburn (UV) so I was in pretty poor shape ... had to go to the emergency room to get an X-ray...